Whose third eye .Yours or lord shiva's.If it's the latters there will be destruction and chaos in the world. That's what Indian mythology says. The third eye if opened emits fire which destroys evil. If its human beings third eye, It denotes the sixth sense .Intuitive powers getting stronger. If you concentrate you can do that. Practise meditating. Don't put too much effort. Just sit or lie down and relax daily for ten minutes. Continue for sometime ,do it whenever you feel like doing it. Slowly you notice your you get intuitions about many things which will really happen. Its called the power of visualization.